At present, near field communication involves two processes, approach detection and data transmission. A touch screen terminal sends an approach detection sequence (for example, an approach detection sequence formed by 6 frequency points); multiple frequency points supported are sequentially scanned; after a response sequence is received from another touch screen terminal, if the signal strength at each frequency point is greater than a predetermined signal strength threshold, it is considered that a signal source is presented at the frequency point; and upon completion of the scanning, if a signal source is present at each of all the frequency points, it is determined that the sequence is valid. After multiple sequence identifications are successful according to an interaction rule, it is determined that a touch screen terminal approaches, and data starts to be sent or received.
However, during communication between a touch screen terminal and an external device, because such interference sources as LCD (for example, the driving signals) and special pictures (for example, gamma maps) would cause interference to the approach detection, therefore the approach detection of the touch screen terminal encounters an error. For example, when the interference is greater or the interference is small but is in coincidence with the valid detection sequence of the approach detection, misjudgments of the approach detection may be caused, such that when no device that needs approach detection approaches, the touch screen terminal considers by mistake that the approach detection is successful in communication and data transmission or data reception starts. In this case, the communication would apparently fail. Therefore, the anti-interference capabilities of the approach detection are poor, and the stability is poor; and thus the LCD interference and different application scenarios may cause an error to the approach detection. As a result, the communication stability of the touch screen terminal varies greatly in different LCD interference strengths and different application scenarios.